The present application claims priority to provisional U.S. patent application Ser. No. 61/137,741, filed on Aug. 1, 2008 and entitled “Method and System of New Topology for Enhanced Ultra-Low-Cost, High-Efficiency, DC-to-DC Step-up Converter,” the disclosure of which is hereby incorporated herein by reference.
FIELD OF THE TECHNOLOGY
At least some embodiments disclosed herein relate to voltage conversion in general and, more particularly but not limited to, voltage conversion for direct current energy sources, such as solar panels, fuel cells, etc.
- Top of Page
Solar panels and other kinds of energy sources produce variable voltages, which, depending on the type of panel, may range anywhere from 10 to 60 volts (and to 70 volts in some instances). It is known to the inventors that there are efforts to combine solar panels with a high-voltage bus (e.g., in the 200 to 600 volt range), which may be implemented via step-up converters that have an output voltage larger than its input voltage.
A discussion of some current DC-to-DC converter topologies can be found on the web site http://www.boostbuck.com/, which includes discussions of boost-buck switching converter, Cuk Converter, Coupled Inductor Cuk Converter, and Integrated Magnetics Cuk Converter. Other topologies for direct current voltage conversion include boost converter, buck converter, flyback converter, etc.
A boost converter typically includes at least two switches, such as a diode and a transistor, and at least one energy storage element, such as an inductor. The transistor is used to periodically connect the energy source directly to the energy storage element to store energy into the energy storage element; and the energy storage element causes the converter to output a voltage higher than its input DC voltage. Filters made of capacitors can be added to the output of the converter to reduce changes in its output voltage. The diode prevents the electric current in the output from flowing backwards.
However, one of the problems with existing direct current to direct current (DC-to-DC) converters is that in some cases their low efficiency may erase a good part of the gains made by using a high-voltage bus.
What is needed is an ultra-high-efficiency, DC-to-DC step-up converter that allows voltages to be transformed for a high-voltage bus typically in the 100 to 600 volt range, and that at the same time uses a very few low-cost components.
- Top of Page
OF THE DESCRIPTION
Methods and systems with a step-up converter based on a boost converter are described herein. Some embodiments are summarized in this section. In one aspect, a step-up converter includes: a boost converter having a first inductor; a second inductor paired on a core with the first inductor; and a rectifier circuit coupled with the second inductor to generate a direct current output.
In one embodiment, the rectifier circuit includes a half bridge rectifier circuit. The half bridge rectifier circuit may include a first diode and a first capacitor connected to the second inductor to form a loop to allow electric current to go through the inductor in a first direction; and a second diode and a second capacitor connected to the second inductor to from a loop to allow electric current to go through the inductor in a second direction.
In one embodiment, the boost converter provides a first portion of a voltage output of the step-up converter; and the rectifier circuit provides a second portion of the voltage output of the step-up converter. The first portion and the second portion of the voltage output of the step-up convert are proportional to a ratio between the first inductor and the second inductor.
In one embodiment, the boost converter further includes a transistor to implement a switch in the boost converter; the voltage output of the step-up converter is higher than 100 volts; and the transistor has a breakdown voltage lower than 100 volts. In one embodiment, the breakdown voltage of the transistor is lower than 75 volts.
In one embodiment, the between drain source connection in the transistor is less than ten milliohms when the transistor is in a saturated on mode; and the output voltage of the boost converter is no more than 50 volts.
In one embodiment, the boost converter further comprises a transistor to implement a switch in the boost converter and a microprocessor coupled to the transistor to control the switch. The microprocessor may be configured to control the switch to adjust an output voltage of the step-up converter.
In one embodiment, the input to output voltage ratio of the step-up converter is higher than 1:8.
In one embodiment, outputs of the boost converter and the rectifier circuit are connected in serial.
In another aspect, a solar panel includes: at least one solar cell to generate a direct current input; a boost converter having a first inductor, the boost converter to receive the direct current input from the at least one solar cell and to generate a first portion of a direct current output; a second inductor paired on a core with the first inductor; and a rectifier circuit coupled with the second inductor to generate a second portion of the direct current output.
In one embodiment, the direct current output has a voltage no less than 200 volts; and the boost converter operates under 100 volts.
In another aspect, an energy system includes: a plurality of direct current energy sources; a voltage bus; and at least one step-up converter coupled between the direct current energy sources and the voltage bus, the step-up converter comprising a boost converter having a first inductor, a second inductor paired on a core with the first inductor, a half bridge rectifier circuit coupled with the second inductor, outputs of boost converter and the half bridge rectifier circuit being connected in serial to power the voltage bus.
In one embodiment, the voltage bus has a voltage equal to or above 200 volts; and the boost converter operates under 50 volts. The energy sources may include solar panels; and the boost converter may include a trench transistor having less than ten milliohms in resistance between drain source when the transistor is in on mode.
The disclosure includes methods and apparatuses which perform these methods, including data processing systems which perform these methods, and computer readable media containing instructions which when executed on data processing systems cause the systems to perform these methods.
Other features will be apparent from the accompanying drawings and from the detailed description which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
- Top of Page
The embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements.
FIG. 1 shows a converter according to one embodiment.
FIGS. 2-3 illustrate waveforms in various locations in the converter illustrated in FIG. 1.
FIG. 4 shows an energy system according to one embodiment.